1. Field of the Invention
The invention relates to silver halide color photographic light-sensitive materials and more particularly to a silver halide color photographic light-sensitive material capable of displaying such an excellent photographic characteristics as sensitivity, gradation, color-developability and the like even when developing it with a color-developer not substantially containing any benzyl alcohol.
2. Description of the Prior Art
Conventionally, a silver halide color photographic light-sensitive material is color-developed, after exposed imagewise, with an aromatic primary amine color developing agent in the presence of cyan, magenta and yellow couplers. In this process, the silver halide micro-crystals of the exposed silver halide color photographic light-sensitive material are reduced by the color developing agent and the oxidants simultaneously produced of the color developing agent take part in a coupling reaction with the couplers, so that a color photographic image comprising cyan, magenta and yellow dyes may be formed.
In this type of processes, a silver halide emulsion layer contains couplers in advance, that is, the so-called coupler-in-emulsion type color developing process is popularly used.
Cyan, magenta and yellow couplers each to be used in this coupler-in-emulsion type color developing process should be fixed into the respective silver halide emulsion layers which are selectively blue, green and red sensitive, so as to avoid the mixing of color. For these couplers, those couplers having, in their molecules, a long-chain aliphatic group serving as a ballast group are used. Because these couplers each have a hydrophobic ballast group, the couplers are usually dissolved in a high boiling organic solvent and are then dispersed, in the form of oil-droplet like colloidal particles, into an aqueous gelatin solution.
A silver halide color photographic material containing such couplers having the hydrophobic group is relatively slow in the permeability of a color developing agent into the couplers and is accordingly slow in the color developing speed. Therefore, in order to accelerate the speed, a variety of permeating agents are studied and used. Among them, benzyl alcohol is popularly used as this kind of permeating agent. When processing with a color developer containing it, an excellent color developability of couplers may be enjoyed and it is also possible to obtain a color photographic image capable of displaying the photographic characteristics excellent in sensitivity, gradation, a maximum density and the like.
Now, in order to obtain an excellent color developability in the process of color developing a color photographic light-sensitive material with a color developer containing benzyl alcohol, the contents of benzyl alcohol is normally 10 to 15 m or more per liter of color developer. Benzyl alcohol is low in solubility to water, and it has, therefore, been necessary in an ordinary case to make benzyl alcohol soluble by adding a reasonable amount of such a polyhydric alcohol as ethylene glycol, diethylene glycol, triethylene glycol, glycerol or the like to serve as an auxiliary solvent.
On the other hand, benzyl alcohol is one of the substances useful for a color developing process, however, this substance and polyhydric alcohols are at a high level of such an environmental pollution as a biochemical oxygen demand (BOD), a chemical oxygen demand (COD) and the like. It is, therefore, desired that they are to be used as little as possible or not to be used at all, if possible. In particular, if benzyl alcohol can be limited to use in the amount of not more than 8 m per liter of a color developer, a polyhydric alcohol can also be avoided to use as the auxiliary solvent of benzyl alcohol. In addition to the above, there is a secondary advantage that the environmental pollution level may be lowered.
Accordingly, there have been the demands for and studies on the developments of photographic processes in which a silver halide color photographic light-sensitive material may be color-developed with a color developer containing benzyl alcohol as little as possible or not containing it at all and the color developability of couplers is not degraded, and the developments of the abovementioned silver halide color photographic light-sensitive materials. For example, Japanese Patent Publication Open to Public Inspection (hereinafter called Japanese Patent O.P.I. Publication) No. 50536/1983 has proposed that a light-sensitive material containing 1-aryl-3-pyrazolidone is processed with a color developer to which benzyl alcohol is added in the amount of 2 to 8 ml per liter of the color developer. According to the technique described in this patent publication, any color developability and the density of dyes to a given amount of silver developed cannot be improved and the characteristic curve shows such an disadvantage particularly in the region of a medium density, though a color developing agent may be accelerated to diffuse from the color developer into the emulsion layers of the light-sensitive material.